Why do HOAs even exist, if everyone hates them so much?

You really have no idea, do you?  Well, the internet has plenty to read about it.  

I had never heard of an hoa until Randy mentioned his years ago. We don't have them here. We get to do pretty much what we want with our homes/property here.

They exist to protect property values. 

Most new subdivisions start out with an HOA/POA so if you want to live there joining is a requirement.  

We moved from a house because we were told there was not one but would be later and we would have a say in the rules etc.  Then it came up that there was one and there were rules already.  Rules we did not agree with.